HP targets silicon photonics

PORTLAND, Ore.  Using silicon photonics to connect blades, boards, chips and eventually cores on the same chip has become a strategic goal for Hewlett Packard Co.

Technology efforts were described in HP Labs' first annual Photonic Interconnect Forum this week (May 12) in Palo Alto, Calif.

By harnessing its expertise in nanoimprint lithography to fashion low-cost, high-speed silicon photonic devices, HP said it hopes to seed the fledgling community of optical interconnect component makers. Rather than doing it all, HP is seeking partners with other silicon photonic pioneers in hopes of developing its first optical interconnect technology in products by 2009.

"I hope that by next year's Photonic Interconnect Forum, we will be able to give product demos instead of just research results," said HP Fellow and CTO Terry Morris. "Our business strategy is to pull parters along and build a community that benefits from the intellectual property at HP Labs--a community that provides the ecosystem to enable the delivery of photonic interconnects in volume."

HP described its laboratory demonstrations of the components needed for creating optical interconnects that handle communication among systems and boards, including two versions of an optical interconnect--a free-space bus (that beams light through air) and a photonic-fiber bus.

Its free-space optical connection provided a 240 Gbit/s optical connection that beamed information through the air between boards. Researcher also described a MEMS micro-lens scanner fabricated from silicon-on-insulator that focuses between-board lasers.

"We have characterized just what we need to make photonic connections work, making very detailed measurements of vibration and board offset and all the other parameters that needed to be characterized in order to quantify the operating environment for photonic interrconnects," said Morris.

HP Labs also showed how its optical bus could haressed nanoimprint lithography to fashion cheap plastic waveguides, micro-lenses and beamsplitters. Its first demonstration was of a 10-bit-wide optical data bus that used just 1 milliwatt of laser power to interconnect eight different modules at 10 Gbit/s/channel for an aggregate bandwidth of over 250 Gbit/s.

"What we are working toward now are novel optical connections, such as board-to-board connections using a photonic bus that enables us to replace an 80-watt chip that performs the electronic switching function today with a molded piece of plastic," said Morris.

Most photonic interconnects use vertical cavity surface-emitting lasers (VCSELs), but HP Labs also showed inexpensive methods of eliminating the need for expensive gallium arsenide chips, using plasmonic LEDs that could cut costs, and a silicon ring resonator that it hopes to fashion with imprint lighography.

"HP Labs has already demonstrated one of the world's smallest and lowest power silicon ring resonators. Now we want to show how to do it with nanoimprint lithography because a dense pattern that takes 60 hours to create with e-beam lithography could take only 30 minutes for nanoimprint lithography," Morris claimed.